SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '698ff1e3a3a71ad266a395904567c2c83463cb2f45738808adffdb403896cada' 
  AND token = 'U65aMzPbT9sulSS6K8dgxS3zUTeUqLHEP0r6dSNyjsE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}